Half a century ago, a devoted science fiction reader could keep up with nearly all the short fiction in the field by following a handful of magazines. Today there are still only a handful of print magazines, but the venues for short fiction have exploded to include online zines, original anthologies, chapbooks, story collections and too many websites to count. This is one reason that best-of-the-year anthologies, which have been a staple of the field since the end of the pulp era, are more important than ever for readers who want a sense of short fiction but lack the time or the zeal to keep up on their own.

Two of the best annuals are those edited by Jonathan Strahan and Gardner Dozois, and there are good reasons to check out both. For one thing, of the 32 stories in Dozois' huge volume, only seven also appear in Strahan's (which has 28 stories). For another, each editor has a slightly different mission.

Dozois, now in his fourth decade of compiling these annuals, confines himself to science fiction — no fantasy or horror — and this can be important to purists. The sheer size of his volume also permits him to include long novellas such as Damien Broderick's "Quicken," a thoughtful living dead story (based on a classic by Robert Silverberg) that puts recent zombie-fests to shame; Jay Lake's "Rock of Ages," a complex thriller in which Seattle is imperiled; and Robert Reed's "Precious Mental," a far-future tale of the search for a derelict spaceship that has been missing for millions of years.

But there are also stories much closer to home, such as Nancy Kress' "Pathways," a touching exploration of the disorder called familial insomnia; Greg Egan's "Zero for Conduct," about a young Afghan girl whose brilliance in computer science and chemistry leads to a major scientific discovery — but gets her in trouble in school — and Val Nolan's "The Irish Astronaut," an almost purely realistic tale of an American astronaut visiting the Irish village that was home to a colleague killed in a space disaster.

Strahan's "The Best Science Fiction & Fantasy of the Year," as the title indicates, includes fantasy stories, and while this limits his coverage of pure-quill science fiction, it permits Neil Gaiman's "The Sleeper and the Spindle," a surprisingly effective mashup of familiar fairy tales, and Sofia Samatar's insightful combination of mermaid lore and family tensions, "Selkie Stories Are for Losers."

The mysteriously pseudonymous K.J. Parker offers a shrewdly satiric account of the invention of a sun-worshipping religion that gets out of hand in "The Sun and I," while on the science fiction side of the ledger, the brilliant Ted Chiang offers a deeply thoughtful meditation on the relative importance of remembered versus recorded experience in "The Truth of Fact, the Truth of Feeling." M. John Harrison — one of Britain's premier writers of any sort — is represented by the haunting and beautiful "Cave and Julia."

Of stories included in both volumes, James Patrick Kelly's "The Promise of Space" concerns a wife trying to communicate with her badly injured astronaut husband, uncertain whether she's talking to him or to the artificial intelligence that is supposed to assist his damaged brain, and Lavie Tidhar's "The Book Seller" offers both a future space-exploring Israel and a tribute to classic science fiction.

One of the oddest and most delightful stories, Geoff Ryman's "Rosary and Goldenstar" brings together a young Shakespeare with the Elizabethan alchemist John Dee, the Danish astronomer Tycho Brahe, and two figures who later become inspirations for the Bard's characters. Don't even ask.

Authority

By Jeff VanderMeer, Farrar, Straus, and Giroux, 344 pages, $15

In his own fiction as well as in his work as an editor and publisher, Jeff VanderMeer has probably done as much as anyone to define "the weird" as a viable mode of fiction that may include elements of science fiction, fantasy, horror, surrealism and magic realism, but that can't be contained by any of those categories. His "Southern Reach" trilogy — three novels being published within months of each other, with the first, "Annihilation," having appeared in February and the third, "Acceptance," due in September — might well serve as a demonstration of the literary possibilities of this form.

"Annihilation" introduced us to a mysteriously transformed part of the Southern American landscape called Area X and detailed the disastrous 12th expedition into that region, which seems to do strange things to all who enter it. "Authority," the middle volume, calls into question a lot of what we thought we learned in that first novel as well as the reliability and even identity of that novel's unnamed narrator.

But "Authority" also calls into question much of what we thought we knew about trilogies. Instead of simply continuing the "Lost"-like adventure of exploring more and more bizarre mysteries, "Authority" is very different in tone and setting. While the first novel took place entirely inside Area X, this one takes place entirely outside it, in a Kafkaesque government bureaucracy charged with managing the explorations.

John Rodriguez — whose nickname "Control" becomes increasingly ironic — is faced with making sense of not only the contradictory views of the last expedition's survivors but of emerging secrets about earlier expeditions, his own memories of his childhood, and his problematic relations with his parents. As the mysteries deepen, we're left with genuine suspense over what further revelations the final volume might hold.